The present invention relates to a scale, especially for weighing individuals, comprising a pedestal, a moveably retained table and at least one measuring element possessing an electrical conductor, wherein the table is operatively connected with the conductor, in order to elongate the same as a function of the weight which loads the table and to alter its electrical resistance.
There are known to the art scales wherein the table is operatively connected with one or two resistance strain gauges serving as measuring elements. Such resistance strain gauges usually contain a deformable strip-like carrier. Arranged on this carrier is an electrically conductive wire which approximately forms a single-layer winding or can extend in a zig-zag configuration. In each case the wire is arranged in such a way that it is elongated upon elongation of the resistance strain gauge, and thus, alters its electrical resistance. This resistance change can be detected by means of a suitable circuit and employed for determining weight.
With each of these heretofore known scales there are provided, in addition to the resistance strain gauges, mechanical guide elements which moveably connect the table with the pedestal and guide such that it can be vertically displaced. Furthermore, there is provided at least one restoring spring which loads the table with an upwardly directed force. In order that there is possible a more or less exact weight measurement by means of the resistance strain gauges, the mechanical guide elements must provide a guide which is practically free of play in order to prevent, on the one hand, horizontal displacements, and on the other hand, must render possible a vertical movement of the table which is as free as possible of friction. These requirements can only be rendered compatible with one another with difficulty and necessitate a relatively expensive construction.